From owner-freebsd-stable@FreeBSD.ORG Tue Jul 15 15:20:35 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4B1CB1065682; Tue, 15 Jul 2008 15:20:35 +0000 (UTC) (envelope-from petefrench@ticketswitch.com) Received: from constantine.ticketswitch.com (constantine.ticketswitch.com [IPv6:2002:57e0:1d4e:1::3]) by mx1.freebsd.org (Postfix) with ESMTP id F1D4C8FC22; Tue, 15 Jul 2008 15:20:34 +0000 (UTC) (envelope-from petefrench@ticketswitch.com) Received: from dilbert.rattatosk ([10.64.50.6] helo=dilbert.ticketswitch.com) by constantine.ticketswitch.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.69 (FreeBSD)) (envelope-from ) id 1KImKO-000Df3-Ta; Tue, 15 Jul 2008 16:20:32 +0100 Received: from petefrench by dilbert.ticketswitch.com with local (Exim 4.69 (FreeBSD)) (envelope-from ) id 1KImKO-000Gqk-ST; Tue, 15 Jul 2008 16:20:32 +0100 To: koitsu@FreeBSD.org, sven@dmv.com In-Reply-To: <20080715145426.GA31340@eos.sc1.parodius.com> Message-Id: From: Pete French Date: Tue, 15 Jul 2008 16:20:32 +0100 Cc: freebsd-stable@freebsd.org Subject: Re: Multi-machine mirroring choices X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 15 Jul 2008 15:20:35 -0000 > However, I must ask you this: why are you doing things the way you are? > Why are you using the equivalent of RAID 1 but for entire computers? Is > there some reason you aren't using a filer (e.g. NetApp) for your data, > thus keeping it centralised? I am not the roiginal poster, but I am doing something very similar and can answer that question for you. Some people get paranoid about the whole "single point of failure" thing. I originally suggestted that we buy a filer and have identical servers so if one breaks we connect the other to the filer, but the response I got was "what if the filer breaks?". So in the end I had to show we have duplicate independent machines, with the data kept symetrical on them at all times. It does actually work quite nicely actually - I have an "'active" database machine, and a "passive". The opassive is only used if the active fails, and the drives are run as a gmirror pair with the remote one being mounted using ggated. It also means I can flip from active to passive when I want to do an OS upgrade on the active machine. Switching takes a few seconds, and this is fine for our setup. So the answer is that the descisiuon was taken out of my hands - but this is not uncommon, and as a roll-your-own cluster it works very nicely. -pete.